HF-surgical devices are well known and German A-documents 3151991, 3911416 or 3942.998 are referred to by way of example. Moreover, reference is explicitly made to these printed publications for the explanation of all details not described in detail herein or other technical design of HF-surgical devices.
Known HF-surgical devices, like other electro-medical devices, have a number of problems. For instance, electro-medical devices require galvanic separation between the primary-side power supply and the patient/user unit. This galvanic separation generally occurs in HF-surgical devices by means of a separation transformer. The separation transformer may be either a transformer connected immediately to the primary alternating voltage, or may be a component of a primary timed combinational circuit unit.
High performance high-frequency surgical devices generally have an output power of at least 400 W. Depending upon the efficiency of the transformer, this generally requires a transformer of at least 600VA to power the surgical device.
Therefore, the primary transformer, utilized as a separation transformer, must be very large and heavy. If however, a combinational primary circuit unit is employed, the required transformer may be relatively lightweight, because usually frequencies between 50 and 100 kHz are utilized. However, a disadvantage in utilizing this type of device is the comparatively high cost of the device, and the physical size of the device is still an issue.
A second problem with high-frequency surgical devices is that many times there are several high-frequency generators and several outlets depending on the mode of operation, for instance; cutting or coagulating, bipolar, monopolar, etc. This may mean that a particular outlet may be connected to a number of various high-frequency generators for various procedures. However, in order not to endanger the patient or the physician/user, it is important that the high-frequency energy is only switched to the selected outlet.
For switching between the outlets and the generators, a relay matrix having make contacts as operating contacts is utilized so that non-utilized outlets are not connected to the generator electronics when the device is switched off. Device failures may occur such that an outlet that should be switched off is incorrectly connected to the generator electronics. This may occur if, for instance, a contact of the relay sticks or jams. Errors causing the relay to fail to close, such as, if the relay coil is interrupted or has a short circuit, are much less frequent.
In addition, relays characteristically require a relatively large quantity of power in order to pick up and/or contact. This power must be supplied by an internal power supply, usually by an “auxiliary power supply” for the electronics control unit of the high-frequency surgical device. This in turn, creates a situation where the auxiliary power supply highly loaded. Therefore, it is desirable to reduce the power intake and/or requirements for the relay.